Conventional large-opening juicers are generally provided with a safety cover and a safety switch at an upper end of a feeding opening in order to ensure safety in working. When the safety cover is opened, the safety switch is triggered to turn off the power, and the juicer stops working. When the safety cover is closed, the safety switch is triggered to turn on the power, and at this time, the juicer begins to work. When a user continuously feeds fruit and vegetable materials for juicing, the user needs to open and close the safety cover frequently, which is inconvenient for the user, and adversely affects the user experience, and may also inevitably cause the juicer to start and stop working frequently. Accordingly, high reliability requirements are imposed on the safety switch and the electric control system of the machine, and costs will be increased significantly, moreover, frequent starting and stopping may exacerbate wear of the machine, and shorten the service life of the machine.